JH, have you considered using laser trimmed multipliers? IMHO, they are pretty fantastic.

AD633 ?

This doesn't perform triangle to sine conversion!

I have considered the 633, because it's smaller and needs less external components.
But it's more expensive, harder to get, has no second source (AFAIK), and you still need to trim the offsets on each input. The only real advantage is that it cancels the quadratic feedtru term internally, without trimming. You need to to this with an extra trimpot on a MC1496. (Well, it's rarely done; I haven't had it in the FS-1 either. I learned about this from the EMS VCS3 ringmod circuit: With the offset trimmer, you minimise carrier bleedthru. What remains then, is a slight bleedthru at _twice_ the carrier frequency. You can suppress this with an extra trimpot. When you do this, the your bleedthru specs come close to an AD633.)

So with an AD633, I'd have one trimmer less than with a MC1496.
But I'd have to implement the whole triangle-to-sine conversion (with trimmers, of course!) with a separate circuit.

The beauty (if I may say so) of my 1496-based circuit is that it uses the input transitors of the multiplier to _also_ perform the required triangle-to-sine conversion! So you can drive the modulators directly with a set of quadrature triangle signals. The Sine conversion is even better than the overdriving-OTA method that is often seen, because it uses a degenerated emitter transistor pair, which allos for lower THD than just a differential pair. (It is not as good as a two-stage approach, like the Moog Modular VCOs use, though.)

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

I think the preselection is one part of the DIY thing and has to make fun
Honestly, if somebody can not calibrate a diy project with standard tools like a good multimeter hes not ready for that kind of project. If we go to more advanced stuff like osci, frequ counter and so on it may be different. But even for the blacet kits you need these tools, so ...

I really would prefer to see you continue developing and sharing nice or crazy things, then to see you suffering selecting and soldering 100reds of caps.

FS-2 was planned as a standalone unit, but then became part of the Matrix FX, where it's called "SSB Mod" (Single Sideband Modulator).
It uses insanely expensive parts (partly for reasons that lie in the context of the Matrix FX, and don't have much to to with frequency shifting).

What I'm going to bring to PCBs is an updated version of the FS-1.
Inexpensive components, good quality, thru-zero carrier, capability of slow barberpole phasing.

Can't avoid a lot of trimmers, though.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

That way, wiring will be kept reasonable, *and* the board size isn't too big for MOTM or similar synthesizers.

JH.

unfinished_main_fs1a_pcb.jpg

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Teaser screenshot of yet unfinished FS-1A main board

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_________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

sorry, i am a little bit new here... what is the dome filter exactly, and how does it relate to this frequency shifter?

thanks!

It's an essential part of the Frequency Shifter (at least of that specific method of frequency shifting).

Mathematically, it's an approximation of a Hilbert transformation - which produces a phase shift of exactly 90 deg (+/- a very small error) for any frequency within a certain range (within the whole audio range, in that case).

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

sorry, i am a little bit new here... what is the dome filter exactly, and how does it relate to this frequency shifter?

thanks!

It's an essential part of the Frequency Shifter (at least of that specific method of frequency shifting).

Mathematically, it's an approximation of a Hilbert transformation - which produces a phase shift of exactly 90 deg (+/- a very small error) for any frequency within a certain range (within the whole audio range, in that case).

ok, so then if without this filter the board may be euro compatible, would the smaller filter board be particularly difficult to mount behind a euro rack faceplate with it? i am assuming that you just meant it didn't fit on one pcb...correct?

sorry, i am a little bit new here... what is the dome filter exactly, and how does it relate to this frequency shifter?

thanks!

It's an essential part of the Frequency Shifter (at least of that specific method of frequency shifting).

Mathematically, it's an approximation of a Hilbert transformation - which produces a phase shift of exactly 90 deg (+/- a very small error) for any frequency within a certain range (within the whole audio range, in that case).

ok, so then if without this filter the board may be euro compatible, would the smaller filter board be particularly difficult to mount behind a euro rack faceplate with it? i am assuming that you just meant it didn't fit on one pcb...correct?

thank you

I'm not so good at mechanical stuff - you have to figure out a clever way to mount it behind the front panel of your choice. I was only talking about the board size, not about compatibility with (Euro) rack systems.

Two boards; one 160 * 100, one 160 * 45.

ETA: that's not quite right; see below ...

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)Last edited by jhaible on Mon Jul 02, 2007 2:19 pm; edited 1 time in total

I'm not so good at mechanical stuff - you have to figure out a clever way to mount it behind the front panel of your choice. I was only talking about the board size, not about compatibility with (Euro) rack systems.

Two boards; one 160 * 100, one 160 * 45.

JH.

A complex and expensive project, but a very interesting sound effect.
I would take this two boards.

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